Final States in Charmed Particle Decays

Abstract

It is shown how weak decays of charmed particles provide information on the isospin of the charm-changing weak interactions, multi-particle production, enhancement of nonleptonic weak interactions, unseen decay modes of known charmed particles and best ways in which to discover new ones, and possible new weak currents and new fermions.

A description of tests for weak decays of heavy mesons is given by Benjamin W. Lee, C. Quigg, and Jonathan L. Rosner, Comments in Nuclear and Particle Physics, to be published. The most conclusive of these tests makes use of the Dalitz-plot analysis of Charles Zemach, Phys. Rev. 133, B1201 (1964), and has been used in Ref. 10 to infer that the D is decaying weakly.Google Scholar

Early emulsion events, including those of Refs. 34 and 35, are discussed by K. Hoshino et al., in Proceedings of the 1975 Cosmic Ray Conference (op. cit. Ref. 35) papers no. HE 5–11, p. 2442, and HE 5–12, p. 2448, and by G.B. Yodh, in Proceedings of the 1975 Cosmic Ray Conference (op. cit. Ref. 35), P. 3936. The importance of asso- ciated production in reducing background from nuclear interactions is stressed by Yodh and in Ref. 38.Google Scholar

Using data quoted in Ref. 27 on up to 7-prong annihilations, I have checked that the sum of all pionic annihilations constructed with the help of tables of Ref. 19 is only about 2/3 of the actual total.Google Scholar

I thank D. Horn for a discussion of more general parametrizations, including the Gaussian distribution. A Gaussian would be suitable for describing the distribution if its center and width were fixed by the data. With present uncertainties in branching ratios (see Ref. 9), this is not possible.Google Scholar

Ref. 13 contains an additional assumption which is not compatible with present data (see Refs. 6–10) or with the discussion of Sec. IV. A, namely, the fixing of c in Eq. (IV.5), and hence of n, a priori.Google Scholar

The factor of 2 on the left of Eq. (VI.4) comes from our assumption of CP invariance, since only the sum for particles and antiparticles is quoted. Tests of CP invariance in decays of charmed particles are noted by A. Pais and S.B. Treiman, Phys. Rev. D12, 2744 (1975), and Maurice Goldhaber and Jonathan L. Rosner, to be published in Phys. Rev. D15 (1977). For an extensive review of a class of models for CP violation see H. Harari, “Beyond Charm”, lectures delivered at Les Houches Summer School, August, 1976, Weizmann Institute report WIS-76/54 PH, to be published.Google Scholar

I am indebted to Arthur Halprin for suggesting this rest.Google Scholar

89.

Note added: (I am indebted to S. Nussinov for discussions leading to the following remarks): An alternative version of the nonet ansatz, consistent with the 6 dominance assumption, is the following: if D° = oil -~ s u d ú - K° + (n or n’), the n and n’ must be produced through the u ú state, so that one finds the ratio listed in parentheses in Eq. (V.7). This then leads to the alternative conclusions in parentheses in Eqs. (V.8) and (V.9). Similarly if F+ = c s -} s u d g -3–7 + (n or n,), the n and n’ must be produced through the s g state, leading to a ratio of F (p+ ÷ T+n’)/F(F+ -3- î+n) which is l/4 that obtained in Ref. 32. The numbers in parentheses in Table VIII are based on the assumption that the n and n’ are produced via the s g state.Google Scholar